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How can I rename a database column in a Ruby on Rails migration?
...FixColumnName
# creates db/migrate/xxxxxxxxxx_fix_column_name.rb
Then edit the migration to do your will:
# db/migrate/xxxxxxxxxx_fix_column_name.rb
class FixColumnName < ActiveRecord::Migration
def self.up
rename_column :table_name, :old_column, :new_column
end
def self.down
#...
Setup RSpec to test a gem (not Rails)
It is pretty easy with the added generator of rspec-rails to setup RSpec for testing a Rails application. But how about adding RSpec for testing a gem in development?
I am not using jeweler or such tools. I just used Bundler ( bundle gem my_gem ) to setup the structure for the new gem and edit the *...
How to find the extension of a file in C#?
... This allows someone to just rename any file *.flv and upload it. Depending on what your requirements are, you might want to check the MIME type as well.
– David Glenn
Dec 11 '09 at 9:44
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Trimming a huge (3.5 GB) csv file to read into R
...has a lot of detail and incomplete rows (leading Access and SQL to choke). It's county level data set broken into segments, sub-segments, and sub-sub-segments (for a total of ~200 factors) for 40 years. In short, it's huge, and it's not going to fit into memory if I try to simply read it.
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Compare two files line by line and generate the difference in another file
I want to compare file1 with file2 and generate a file3 which contains the lines in file1 which are not present in file2.
1...
How do I get whole and fractional parts from double in JSP/Java?
...follow
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edited Nov 26 '19 at 14:48
Dan Is Fiddling By Firelight
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Best way to work with dates in Android SQLite [closed]
I'm having some trouble working with dates on my Android application that uses SQLite.
I have a couple questions:
9 Answers...
Why not use java.util.logging?
For the first time in my life I find myself in a position where I'm writing a Java API that will be open sourced. Hopefully to be included in many other projects.
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In Firebase, is there a way to get the number of children of a node without loading all the node dat
...e snippet you gave does indeed load the entire set of data and then counts it client-side, which can be very slow for large amounts of data.
Firebase doesn't currently have a way to count children without loading data, but we do plan to add it.
For now, one solution would be to maintain a counter ...
How to convert NSNumber to NSString
So I have an NSArray "myArray" with NSNumber s and NSString s. I need them in another UIView so i go like this:
7 Ans...